According to functionalism mental states are functional states; a disposition to behave in particular ways and to have
certain other mental states, given certain inputs from the senses and certain other mental states. In other words, we
can give an analysis of what mental states are in terms of their input and outputs. For example, the mental state
‘pain’ may be understood as an ‘inner state’ that converts bodily harm (input) into the disposition to cry (output).
Functionalism doesn’t take a position on the substance of these mental states (i.e. what they are composed of),
accepting that they can be multiply realised. Thus, functionalism is compatible with physicalism and dualism.
Given that functionalism claims that we can give a complete account of the mind in terms of functional states, quale
poses a significant objection. This is because quale is considered by many philosophers to be intrinsic; sui generis
and cannot be understood or analysed in terms of something else (e.g. inputs and outputs). For example, the quale
of ‘what it is like to experience the colour red’ cannot be reduced to or explained by any physical, functional or
behavioural properties. Given its significance, this essay will focus on three objections to functionalism that centre
qualia: the possibility of a functional duplicate with different qualia, the possibility of a functional duplicate with no
mentality/qualia, and Jackson’s ‘knowledge/Mary’ argument. However, it will be concluded that none of these
objections provided us with sufficient reason to dismiss functionalism as incorrect.
According to the possibility of a functional duplicate with different qualia objection, functionalism is incorrect as it
cannot make sense of inverted qualia (e.g. when A experiences red qualia, B experiences green qualia, and vice
versa). This is a problem for functionalism as A and B are functionally identical (e.g. when asked, A and B both
describe grass as green, tomatoes as red, etc.) but they have different conscious experiences. Thus, functionalism
cannot provide a complete account of the mind.
However, as noted by Patricia Churchland, there would be a functional difference between A and B. True, this
wouldn’t be apparent from asking them to describe the colour of different objects, but it would be apparent if they
took part in a colour-blind test. Hence, given certain tests (input), we would notice that on some occasions A can
identify the ‘hidden’ number while B cannot (output), and vice versa. Thus, we can make sense of inverted qualia
using functional states.
How about, if A and B’s colour qualia were completely inverted? If this was the case, the colour-blind tests would no
longer be helpful as their answers would be identical. If A sees a number, so will B (it will be inverted, but they will
still see it). Maybe so, but as Churchland points out – once again – we would still have a functional difference. This
time however, it wouldn’t be detectable using colour blind tests, but by the difference in ability to discriminate
between different shades of colour. Given that humans are worse at distinguishing between different shades of blue
than orange, when presented with a spectrum of orange shades (input), A should be able to make finer distinctions
than B (output). Thus, we would still have a functional difference. It would appear then, that inverted qualia poses
no threat to functionalism.
Moving on, according to the possibility of a functional duplicate with no mentality/qualia objection, functionalism
must be incorrect as it is possible to imagine a functional duplicate of the human mind that doesn’t have qualia. The
example Ned Block uses is an imaginary China in which every person acts like a neuron, using two-way radios to
communicate with one another and activate nerves in an [unfortunate] body. This China mind can perform all the
same functions as a human brain (it is a functional duplicate), but while we are happy to accept that the latter has
qualia it would seem absurd to suggest the same about the former. Therefore, despite the China mind and human
brain being functional duplicates, they are not mental duplicates (one has qualia and one does not). If we are
persuaded by this thought experiment then it would seem functionalism is incorrect.
At this point, the functionalist may object that the human brain and China mind would not be functional duplicates.
This is because a) the China mind would be vastly slower than the human brain, and b) the China mind would be
prone to many more disruptions and break-downs (radio failure, etc.) than the human brain. However, this is a weak
response, as function does not depend on speed, and human brains are also susceptible to damage and slowing
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